Photographic silver halide photosensitive material, often simply referred to as photosensitive material hereinafter, after exposure, is processed through a series of steps including color development, desilvering, washing and stabilization in the case of color photosensitive material. There are used color developer for color development, bleaching, blix and fixing solutions for desilvering, city water for washing, and stabilizer for stabilization. Black-and-white photosensitive material is processed through a series of steps including black-and-white development, fixation, and washing. In either case, photosensitive material is generally processed by immersing the photosensitive material in the respective solutions which are normally adjusted to a temperature of 20.degree. to 50.degree. C.
In the commercial practice of such processing of photosensitive material, it is desired to achieve stable and acceptable processing performance with a permissible, minimal amount of processing solution for the purposes of reducing the cost, manual work, pollution loads, and processor size as well as improving the commodity value of processed ones.
The stability of processing performance is obtained by maintaining the processing solution composition within a desired range at all times and the superiority of processing performance is obtained by uniform immersion of the photosensitive material in a sufficient volume of processing solution.
Therefore, as found in color development laboratories, the commercial practice of processing color photosensitive material uses an automatic processor having processing tanks containing large volumes of processing solution. The processor is designed such that whenever a predetermined quantity of color photosensitive material has been processed, a replenisher is automatically fed to the used processing solution for compensating for its exhaustion and maintaining the processing solution within the desired composition range.
In response to the diversification of consumers' interest, consumers' desire to get color prints instantaneously, and the public's interest in the color processing business due to small investments and the like, color photosensitive material processing is in the phase of shifting from conventional centralized processing in big laboratories to diversified small quantity processing in many mini-labs and further to small quantity rapid processing.
Processing steps are discussed next. Steps of processing imagewise exposed film, typically development and bleaching steps, use processing solutions which experience a varying degree of exhaustion since the amount of silver to be developed varies with exposure. In the prior art, the operator determined processing conditions by presuming the degree of exhaustion of the processing solution from the known number of film rolls processed or film length. However, since the amount of silver to be developed varies with exposure conditions which in turn, vary with each of exposed picture frames, the degree of exhaustion of the processing solution varies between different film strips. Therefore, for obtaining good and uniform pictures, it is desirable to determine processing conditions for an individual film strip by considering its exposure conditions.
Particularly, in the case of a mini-lab processor intended for small quantity rapid processing, a limited size of processing tank is filled with a relatively small volume of processing solution which experiences a relatively greater degree of exhaustion per roll film. It is therefore desirable to determine processing conditions for an individual roll of film by taking into account the amount of silver developed which varies with the film being used.